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    <title>Document</title>
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    <script>

   var box=document.querySelectorAll('.box')
var   arr=[1,2,3,4,5]
console.log(arr);
// 类数组转成数组
// Array.from(类数组)
console.log(Array.from(box),'????');
  for(var key  in arr){
      console.log(key,arr[key],'fffffffffff');
  }
    </script>
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